Nobody told us A. what to do it B. how to do C. where to do D. when to do it

Nobody told us
A. what to do it
B. how to do
C. where to do
D. when to do it

A. what to do it B. how to do C. where to do (答案→)D. when to do it解析：考查疑问词+不定式的用法。What作do的宾语，it多余，排除A；B、C两项缺少宾语；D项不缺宾语。句意“没有人告诉我们什么时候做这件事。”故选D。

好好学习下